Roll-up tarp apparatus

ABSTRACT

A roll-up tarp apparatus for a truck box having first and second ends, first and second longitudinal sides and an open top. The apparatus includes a tarp, a roll bar, an arm and a biasing member. The first longitudinal edge of the tarp is interconnected to the first longitudinal side of the truck box and the second longitudinal edge of the tarp is attached to the roll bar member. The roll bar is operatively connected to the truck box and is rotatably movable between the first and second longitudinal sides of the truck box, which enables the tarp to close or open the truck box. At least one biasing member is operatively connected to the roll bar or the arm, with the biasing member able to exert a tensioning force in the direction of the second longitudinal side of the truck box so that the tarp is under tension.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/531,767 filed Jun. 25, 2012, which is a continuation of U.S.patent application Ser. No. 12/463,049 filed May 8, 2009, now U.S. Pat.No. 8,226,150, which claimed benefit under 35 U.S.C. 119(e) of both U.S.provisional application Ser. No. 61/051,999, filed May 9, 2008, and U.S.provisional application Ser. No. 61/169,185, filed Apr. 14, 2009. Eachof the aforementioned applications is hereby incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to roll-up tarp apparatuses for an opentop truck cargo box or the like. More particularly, the presentinvention relates to roll-up tarp apparatuses including an elongatedroll bar member that is biased with at least one biasing member.

2. Description of the Related Art

Roll-up tarp apparatuses for truck cargo boxes having an open top arewidely utilized in the trucking industry. For example, U.S. Pat. No.4,505,512 (Schmeichel et al.) discloses a roll-up tarp apparatus for anopen truck box or trailer. The roll-up tarp apparatus includes a tarpmade from a flexible material. The tarp is secured along one side to thetop of the truck box. The other side of the tarp is attached to a rollbar with a plurality of flexible straps. A crank apparatus connected tothe roll bar by a U-joint and collar assembly is utilized to roll thetubular member transversely of the truck box opening so as toselectively enclose the truck box with the tarp or uncover the truckbox. A plurality of hooks is attached to the side of the truck boxopposite of the side to which the tarp is fixedly secured. The hooksretain the roll bar when the tarp is covering the truck box. Other knownroll-up tarp assemblies utilize a crank to control the movement of theroll bar and others, such as that of U.S. Pat. No. 4,673,208 (Tsukamoto)utilize a motorized arm that is interconnected to the roll bar.

In motorized roll-up tarp apparatuses, a biasing member can be used toassist the motor in moving the roll bar in an unroll direction.Typically, a bungee cord is interconnected to a collar located on theroll bar extends from the collar, around a corner of the truck box andalong at least part of the length of the truck box where the second endof the bungee cord is attached. As the tarp is rolled-up across the topopening of the truck box, the bungee cord typically stretches and rubsagainst the corner of the truck box. The constant stretching of thebungee cord along the corner of the truck box is a constant source ofabrasion on the cord, thus reducing the life of the bungee cord andincreasing the strain on the motor when the cord is at a reduced biasingcapacity. As the roll bar rolls up or unrolls the tarp, the arms movethe roll bar across a frame that supports the tarp over top opening ofthe truck box.

Other known roll-up tarp assemblies include springs to bias the arms inthe unroll direction. Spring assists are typically used when the tarp isun-rolled from the front to the back, rather than side to side. See, forexample, U.S. Pat. No. 7,188,887 (Schmeichel) and U.S. Pat. No.7,195,304 (Schmeichel).

The present invention addresses limitations and problems associated withthe related art.

SUMMARY OF THE INVENTION

The present invention provides roll-up tarp apparatuses for an opentruck box or the like. The preferred roll-up tarp apparatus includes atarp made of a flexible material having first and second longitudinalsides. One longitudinal side can be attached to a longitudinal side ofthe truck box and the second longitudinal side is connected to anelongated roll bar member of the roll-up tarp apparatus such that whenthe elongated roll bar member moves across the truck box in onedirection, the tarp is un-rolled from the roll bar to cover the openingof the truck box and when the roll bar moves in a second direction,across a middle of the truck box, the tarp is rolled-up and gathered onthe elongated roll bar member. In order to facilitate movement of theelongated roll bar member, one preferred roll-up tarp apparatus includesat least one arm having a top end and a bottom end. Optionally, the topend of the arm is connected to a motive source with a motor, which isinterconnected to the elongated roll bar member to selectively move theroll bar in unroll and roll-up directions to respectively cover anduncover the opening of the truck box. Alternatively, a crank armassembly can be used to move the elongated roll bar member. The bottomend of the arm can be pivotally interconnected to one opposing end ofthe truck box.

The preferred arm includes a shaft and a sleeve that is moveable alongthe shaft. The preferred shaft has a restricting member such that as thearm moves, the sleeve slides upwardly and downwardly along the shaftuntil the sleeve contacts the restricting member, which prevents thesleeve from moving downward past that point. The restricting member ispreferably positioned on the arm such that the elongated roll bar memberwill be supported substantially over an apex of the truck box when thearm is at an angle of about 90 degrees with respect to a lateral ends ofthe truck box such that any cargo defining a crowned top surface (e.g.grain when initially loaded into the truck box) can be cleared by theelongated roll bar member. In the most preferred embodiments, theposition of the restricting member is adjustable. The higher theelongated roll bar member is supported above the truck box, the morewind can make operation of the roll-up tarp assembly difficult.Therefore, it is preferred that a user can adjust the height therestricting member will support the elongated roll bar member for theparticular conditions present. Alternate embodiments can include aresilient restricting member, such as a spring.

Further, in preferred embodiments, the roll-up tarp assembly includes atleast one roll bar biasing member connected to one of the ends of theelongated roll bar member and, in preferred embodiments, two roll barbiasing members, one connected to each of the respective ends. The rollbar biasing member(s) exerts a force on the roll bar member that placesa tension on the roll bar member and can urge the movement of elongatedroll bar member in the unroll direction when motive force is provided torotate the roll bar. In preferred embodiments, one biasing member isconnected to each end of the elongated roll bar member such that theforces exerted on each end of the roll bar member are generally equalor, alternatively, not equal but the greatest at those positions.Preferably, the roll bar biasing members each include a cordinterconnected to one end of the elongated roll bar member; wherein thecord winds around the elongated roll bar member as the arm directs theelongated roll bar member in the unroll direction. Preferably, eachbiasing member includes a tensioning element having first and secondends, the first end of the tensioning element is interconnected to thecord and the second end of the tensioning element is interconnected tothe second longitudinal side of the truck box. In preferred embodiments,an unwound portion of the cord and the biasing member are arranged andconfigured such that they are generally perpendicular to the elongatedroll bar member and continually tension the elongated roll bar membernot only in the unroll direction but also when the elongated roll barmember is in the latched or secured position. Because the roll barbiasing member is generally perpendicular to the elongated roll barmember, the cord will have a self-aligning tendency, which will providefor generally equal movement of both ends of the elongated roll barmember.

Various preferred roll-up tarp apparatuses include upper and/or lowerarm biasing members interconnected to the top end (or a slidable uppersleeve, as the case may be) and the bottom end, respectively, of atleast one arm. The preferred upper arm biasing member includes anelastic cord interconnected to a generally non-elastic cord and isconfigured such that the generally non-elastic cord will be drawn aroundthe corner of the truck box whereas the elastic cord will extend onlyalong the longitudinal side of the truck box and tarp. The preferredlower arm biasing member includes a torsion spring that urges movementof the respective arm, and thus also the elongated roll bar member, inthe unroll direction. The arm biasing members urge the respective arm inthe unroll direction, thus indirectly biasing the elongated roll barmember in the unroll direction.

In another preferred embodiment, at least one arm with a motive sourceis provided with a converter unit or unit having an input section thatis connected to the motive source and an output section that isconnected to the elongated roll bar member. The converter unit includesa plurality of interconnecting elements or components that are arrangedso that they are able to change the characteristics of the motive sourceso that they are different at the output section of the unit. Theinterconnecting elements include rotatably mounted wheels and an endlessbelt, although sprockets and a chain are preferred. The sprockets canhave different sizes that can effectively change the torque and speed ofrotation of the motor produced at the output section of the unit.Preferably, the sprockets of the unit are selected so as to be able toeffectively increase the torque of the motor at the output section ofthe unit.

Various preferred roll-up tarp apparatuses are arranged and configuredsuch that the cord of the biasing member winds around the elongated rollbar member such that a substantial portion of the wound-up cord isprotected and stowed underneath the latch plate when the elongated rollbar member is in the latched position or, alternatively, the securedposition. Further various preferred biasing members can be arranged andconfigured to exert continual tension on the elongated roll bar member.Continual tension exerted on the elongated roll bar member, particularlywhen the roll bar member is in the secured position, is advantageousbecause, among other reasons, the tension can substantially eliminatelateral swinging of the elongated roll bar member during transit, whichcould damage the truck box and pose other safety concerns, especially ifthe elongated roll bar member were to become disengaged from the latchplate.

These and various other advantages and features of novelty whichcharacterize the present invention are pointed out with particularity inthe claims annexed hereto and forming a part hereof. However, for abetter understanding of the invention, its advantages and objectsobtained by its use, reference should be made to the drawings which forma further part hereof, and to the accompanying descriptive matter, inwhich there is illustrated and described a preferred embodiment of thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, in which corresponding reference numerals and lettersindicate corresponding parts of the various embodiments throughout theseveral views, and in which the various embodiments generally differonly in the manner described and/or shown, but otherwise includecorresponding parts;

FIG. 1 is a perspective view of a roll-up tarp apparatus 10 operativelysecured over a trailer or a truck box 6 of a truck 5 and showing theelongated roll bar member 18 in a partially open position;

FIG. 2A is an enlarged end view of the front, right corner of the truckbox 6 shown in FIG. 1;

FIG. 2B is a view similar to that of FIG. 2A, but illustrating analternate method of securing the upper biasing member 50 a to theelongated roll bar member 18 with a rotatable collar 80;

FIG. 3 is a partial, perspective view of a rear arm 22 b of the roll-uptarp apparatus 10 shown in FIG. 1;

FIG. 4 is an abbreviated perspective view of attachment portions of theinitial preferred upper biasing member 50 a of the roll-up tarpapparatus 10 of FIGS. 1-2;

FIG. 5 is a partial, schematic, end view of the truck box 6 illustratinga front arm 22 a of FIG. 2A further including a restricting member 38 athat can support a tarp 12 above the end cap 8 e of the truck box 6;

FIG. 6A is a partial, schematic, end view of the truck box 6, similar tothat shown in FIG. 5, wherein there is cargo C is particulate materialsuch as grain, delivered into the truck box 6 and the restricting member38 a is supporting the elongated roll bar member 18, and thus, the tarp12 above a mound of the newly delivered cargo C;

FIG. 6B is a partial, schematic view of the arm 22 a as shown in FIG.6A, but showing an alternate restricting member 38 b and including aresilient compression spring 42;

FIG. 6C is a partial, schematic view of the arm 22 a as shown in FIG.6A, but showing an alternate restricting member 38 c;

FIG. 6D is a partial, schematic view of the arm 22 a as shown in FIG.6A, but showing yet another alternate restricting member 38 d;

FIG. 6E is a partial, schematic view of the arm 22 a as shown in FIG.6A, but showing yet another alternate restricting member 38 e;

FIG. 7A is a schematic, end view of the elongated roll bar member 18 asit is in the process of being secured over the trailer or cargo box 6,prior to being in a closed, stored or secured position; the cargo box 6contains a new load of cargo C such as grain or the like, which is shownin a mound in the center prior to the usual shifting of the load thatoccurs over time after the load is delivered, similar to that shown inFIG. 6A;

FIG. 7B is a schematic, end view of the elongated roll bar member 18similar to that shown in FIG. 7A, but as the elongated roll bar member18 is stored in the secured position and illustrating how the flexiblecover 12 is tensioned downwardly to compress the cargo C down into thetruck box 6 as the tarp 12 is tightened on the elongated roll bar member18 against the latch plate 64 a;

FIG. 8 is an enlarged view of a lower arm biasing mechanism 100 of FIG.1;

FIG. 9 is an alternate embodiment of an arm 22 a′, the alternate arm 22a′ interconnected to the side 8 a of the truck box 6 with a ball joint95 and showing the ball 93 in phantom;

FIG. 10 is a side, schematic view of the arm 22 a′ of FIG. 9,illustrating the preferred adjustable range of the arm 22 a′ allowed bythe ball joint 95;

FIG. 11 is a partial perspective view of an alternate biasing member 150connected to one end of the elongated roll bar member 18 of an alternateroll-up tarp apparatus similar to that shown in FIG. 1; but portions ofwhich are shown in phantom;

FIG. 12A is a partial perspective view of the end of the elongated rollbar member 18 of FIG. 11 (certain elements have been omitted forclarity);

FIG. 12B is a partial perspective view of the end of an alternateflexible tarp 12′ connected to the elongated roll bar member 18 of FIG.11;

FIG. 13A is a partial cross-sectional view of the end of the elongatedroll bar member 18 of FIG. 12A;

FIG. 13B is a partial, end view of the elongated roll bar member 18 andtarp 12′ of FIG. 12B when the elongated roll bar member is in anunrolled position;

FIG. 14 is a partial side view of an attachment plate 270 for securing aspring 156, which is a portion of the alternate biasing member 150 ofFIG. 11 to the first side 8 b of the truck box;

FIG. 15 is a front view of the attachment plate 270 of FIG. 14;

FIG. 16A is a partial, schematic end view of the biasing member 150 ofFIG. 11, biasing the elongated roll bar member 18 toward the closedposition when the elongated roll bar member 18 is secured in an openposition and the cover 12 is rolled up on the elongated roll bar member18;

FIG. 16B is a partial, schematic end view of the elongated roll barmember 18 as the elongated roll bar member 18 moves toward the securedposition of FIG. 16C;

FIG. 16C is a partial, schematic end view of the elongated roll barmember 18 in the secured position, wherein the flexible cover 12 is overthe truck box 6 so that the truck box opening (7 a, not shown) isclosed;

FIG. 17A is partial, schematic end view of a second alternate biasingmember 250, similar to that shown in FIG. 11, but including a pulley266;

FIG. 17B is partial, schematic end view of the second alternate biasingmember 250 of FIG. 17A as the elongated roll bar member 18 is movingtoward the secured position;

FIG. 17C is partial, schematic end view of the second alternate biasingmember 250 of FIG. 17A when the elongated roll bar member 18 is in thesecured position;

FIG. 18A is a schematic illustration of the elongated roll bar member 18as it moves from the secured position P1 to the open position P6;

FIG. 18B is a partial, schematic illustration of alternateconfigurations of the roll-up tarp assembly of FIG. 11 in which thebiasing member 150′, 150″, 150′″ can at least partially be secured atnumerous positions within the truck box 6 (as also shown in phantom);

FIG. 18C is an enlarged schematic illustration of cord 158′ of FIG. 18Bexiting the truck box 6 through grommet 170;

FIG. 19 is a partial, perspective, schematic view of arm 22 a includinga motive source 30 and a converter unit 300 to multiply to force of themotive source;

FIG. 20 is a top plan, schematic view of the converter unit 300 of FIG.19;

FIG. 21 is a schematic illustration of the internal arrangement of thecomponents or elements of the converter unit 300 of FIG. 19;

FIG. 22 a is a first graphical representation of the tension (lbs. oftensioning force) on the cord 158 of one preferred embodiment of thebiasing member 150 when the elongated roll bar member 18 is in positionsP1 through P6 as illustrated in FIG. 18A;

FIG. 22 b is a second graphical representation of the tension (lbs. oftensioning force) on the cord 158 of a second preferred embodiment whenthe elongated roll bar member 18 is in positions P1 through P6 asillustrated in FIG. 18A;

FIG. 23 is a partial, perspective view of a crank arm assembly 400connected to the elongated roll bar member 18, which can be substitutedfor the motive force 30 of the roll-up tarp apparatus 10 of FIG. 1;

FIG. 24 is an exploded, perspective view of the elongated roll barmember 18 of FIGS. 1 and 11-13; and

FIG. 25 is an end view of the elongated roll bar member 18 of FIGS. 1,11-13 and 24.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-3 illustrate a truck 5 including a truck cargo box or truck box6 having a bed and four sides 8 a-d. In preferred embodiments, the truckbox 6 can include one or two end caps 8 e and 8 f secured over a top 7of the respective ends 8 a, 8 c of the truck box 6. Each end cap 8 e, 8f includes an end edge, opposing side edges, and a curved outer surface.Note that the top 7 of the truck box 6, which defines a top opening 7 a,will be somewhat foreshortened by the use of one or more end caps 8 e, 8f. Although in some cases, the roll tarp assemblies of the presentinvention will not include end caps, because they are sometimes providedby the truck manufacturer or have been provided with a previously usedroll tarp apparatus, the present invention can include end caps providedfor each end of the truck box 6. Similarly, support bows 9, if requiredand provided, can be provided by the manufacturer of the truck box 6 oralternately provided as a part of an alternate roll-up tarp apparatus. Apreferred roll-up tarp apparatus 10, operatively secured to a truck box6, is shown in these figures. The roll-up tarp apparatus 10 includes aflexible tarp 12 that can be drawn over the top opening 7 a to covercargo C (see FIGS. 6A, 6B) within the truck box 6, an elongated roll barmember 18, two arms 22 a, 22 b positioned at each of the respective ends8 a, 8 c of the truck box 6 and connecting members 44 a, 44 b thatconnect the roll bar member 18 to the respective arms 22 a, 22 b. Thearms 22 a, 22 b selectively control the position of the elongated rollbar member 18, as it is rolling-up (furling) or unrolling (unfurling)the tarp 12. In alternate embodiments of the present roll-up tarpapparatus, discussed herein, there may be only one arm provided.

The preferred flexible tarp 12 is made of vinyl coated polyesterpreferably having a weight of from about 10-22 oz/yd², preferably about18 oz/yd², although lighter or heavier material could be used. Theflexible tarp 12 includes two longitudinal edges 14 a, 14 b and twolateral edges 16 a, 16 b. One longitudinal edge 14 a of the flexibletarp 12 is attached to one respective side 8 d of the truck box 6. Theother longitudinal edge 14 b of the flexible tarp 12 is secured to theelongated roll bar member 18, which is interconnected to two arms 22 a,22 b that are pivotally attached to the respective ends or lateral ends8 a and 8 c of the truck box 6.

The roll-up tarp apparatus 10 preferably further includes a latch plateor rail 64 a, 64 a′ and a plurality of posts or stops 65. The latchplate 64 a, 64 a′ is preferably removably positioned along one side 8 bof the truck box 6, while the support posts 65 are positioned in aspaced apart relation along the opposite side 8 d. The latch plate 64 a,64 a′ includes an innermost edge with a vertically oriented attachmentflange 64 h, 64 h′ and a downwardly facing curved or arcuate surface 64d, 64 d′ that is configured and arranged to receive the elongated rollbar member 18 when the roll bar member is in the latched and securedposition. The downwardly facing curved or arcuate surface 64 d, 64 d′includes an inner longitudinal edge 64 b, 64 b′ and an outerlongitudinal edge 64 c, 64 c′. The vertical flange 64 h, 64 h′ canfurther be attached to a spacer 64 i, 64 i′ which serves to space theinner longitudinal edge 64 b, 64 b′ of the downwardly facing curvedsurface 64 d, 64 d′ away from the side 8 b of the truck box 6,preferably by about ¼ inch to about 1¼ inch. As best illustrated inFIGS. 2A and 11, the preferred latch plate 64 a, 64 a′ is arranged andconfigured such that the elongated roll bar member 18 including thewound up tarp 12 is spaced away from and out of contact with the side ofthe truck box 8 b by spacer 64 i, 64 i′ when the elongated roll barmember is underneath the latch plate 64 a, 64 a′ either in a storedposition or otherwise.

As generally illustrated in FIG. 11 and further discussed below, thelatch plate 64 a′ need not be a unitary structure. The latch plate 64 a′can be segmented and include a plurality of spaced apart sections of anyeffective length spanning the length of the truck box 6. For example,the latch plate 64 a′ can include three sections, one at each end of thetruck box 6 and one in the middle. This generally prevents unnecessarywear damage to the side of the truck box. Preferably, the latch plate 64a′ is provided with spacer 64 i′ that positions the inner longitudinaledge 64 b′ of the downwardly facing receiving surface 64 d′ of the latchplate away from the side of the truck box 8 b; preferably by about 0.25inch.

Further preferred latch plates 64 a, 64 a′ include an outer longitudinaledge 64 c, 64 c′ with a rounded surface 64 f, 64 f′ over which both theflexible tarp 12 and the non-elastic cord 58 can be drawn. Such arounded surface provides a controlled surface with a smooth transitionthat can reduce wear as compared to when the flexible cover 12 and cord58 are drawn over the comparatively sharp, angled edge of the truck box6, which can be rough and abrasive. Optionally, the rounded surface 64f, 64 f′ may include an upwardly facing longitudinal channel 64 g, 64 g′that is configured and arranged to receive moisture and direct ittowards the ends of the latch plate 64 a, 64 a′.

The truck box 6 will preferably include support bars or ribs 9 that spanthe respective longitudinal sides 8 b, 8 d of the truck box 6 and whichprovide support for the tarp 12 above the top opening 7 a of truck box6. Moreover, each end cap 8 e, 8 f is attachable to one end 8 a, 8 c ofa truck cargo box 6 such that their respective edges meet, and theirrespective curved upper surfaces 25 are able to support a portion of aflexible tarp 12 of a roll-up tarp assembly 10 when the tarp assembly 10is in a secured position or when the tarp assembly is moving betweensecured and open positions.

Referring now also to FIGS. 5 and 6A, it is noted that preferred roll-uptarp apparatus embodiments will include two arms 22 a, 22 b, one at eachend of the truck box 6. Each of the arms 22 a, 22 b will preferablyinclude a shaft 36 a, 36 b and a sleeve 32 a, 32 b. The shafts 36 a, 36b are pivotally connected to respective ends 8 a, 8 c of the truck box 6at a point of attachment 23 (see, FIG. 5, only one point of attachment23 for arm 22 a is illustrated, however, it will be understood that thesecond arm 22 b will be attached to the truck box 6 in a similarmanner). Generally, each sleeve 32 a, 32 b is able to freely slideupwardly and downwardly on top ends 24 a, 24 b of respective arm shafts36 a, 36 b so that the roll bar 18, which is connected to the sleeve, isable to follow the general contour of the end plate 8 e as opposed tofollowing an arc described by the top end 24 a of the arm 22 a, 22 b. Inother words, the interaction of the shaft 36 a, 36 b and sleeve arm 22a, 22 b are able to accommodate a varying or variable distance D,wherein the distance can be measured from the center of the pivotalpoint of attachment 23 and a variable point of contact. The point ofcontact can be, for example, established by the elongated roll barmember 18 as it traverses over the end cap 8 e (in general terms, overthe top 7 of the truck box 6, which is generally the resting place forthe roll bar 18 when the tarp 12 is mostly unrolled as shown in FIGS.2A, 2B and 3). The point of contact can also be established by thebottom most portion of the flexible tarp 12 as the tarp is rolled-up (orfurled) on the elongated roll bar member 18 and contacts the uppersurface 25 of the respective end cap 8 e, 8 f, which is interposedbetween the top 7 of the truck box 6. It will be appreciated that thisvariable distance D changes both: 1) as a distance between a variablelocation on the top 7 of the truck box 6 or the upper surface 25 of therespective end cap 8 e, 8 f and the respective center point of pivotalattachment 23 varies through a turn radius of the respective arms 22 a,22 b; and 2) as the tarp 12 is rolled-up on the elongated roll barmember 18 creating varying thickness of gathered tarp 12 on theelongated roll bar member 18. For instance, in the embodiment shown inFIGS. 1-3 and schematically in FIGS. 5 and 6A, the top opening 7 a isalmost completely uncovered when the arms 22 a, 22 b are over as far asthey can go to the left (as shown schematically in phantom in FIG. 5).In this situation, the tarp 12 (not shown for clarity in this Figure)will be almost completely rolled-up on the elongated roll bar member 18and the gathered tarp 12 (see also, FIGS. 2A and 3), which is rolled upon the elongated roll bar member 18 will rest against the respectivesupport posts 65 and on the upper surface 25 of the respective end caps8 e, 8 f.

It will be further appreciated, that the thickness of the gathered tarp12 (see also, FIGS. 2A and 3) on the roll bar member 18 will not liftthe roll bar 18 from the upper surface 25 of the respective end caps 8e, 8 f on each end of the truck box 6, when the roll bar member 18 isclose to the edge of the truck box when the tarp is nearly covering theentire top opening 7 a. In alternate embodiments, where the end caps 8e, 8 f are lower than the bows, support bars or ribs 9 that are providedwith the various truck box 6 manufactured in North America, the bottomportion of the rolled-up tarp 12 (see also, FIG. 2A) may rest on thebows 9, raising the roll bar member 18 the distance of the thickness ofthe tarp gathered on the roll bar as it rests on the bows 9 proximatethe respective ends 8 a, 8 c of the truck box 6 and thereby separatingthe roll bar member that further distance from the respective points ofattachment 23 and raising the rolled-up tarp above the upper surface 25of the respective end caps 8 e, 8 f for a short interval during therespective roll-up and unroll processes. Preferably, the bows 9 arepositioned slightly higher than the end caps 25 to further tension andspread the tarp 12 across the truck box opening 7 a. It will also beappreciated that as the roll bar member 18 moves over the top opening 7a in the direction of the other longitudinal side 8 b of the truck box6, and the tarp 12 is being unrolled in order to cover the top opening 7a, the space between the roll bar member 18 and upper surface 25 of therespective end caps 8 e, 8 f will gradually diminish. Because the arms22 a, 22 b are also turning through a path (not designated) that maydiffer from a contour or radius R of the end caps 8 e, 8 f of the truckbox 6 or the upper surface 25 of the end caps 8 e, 8 f interposedbetween the top opening 7 a and the roll bar member 18, the variabledistance D is also subject to change.

In any case, it will be appreciated that the respective sleeves 32 a, 32b make upward or downward adjustments with respect to the respectiveshafts 36 a, 36 b to accommodate these variations in space and distance,so that the roll bar member 18 can rotate from left to right away fromthe support posts 65, toward the latch plate 64 a, 64 a′, in an unrolldirection, shown in phantom in FIG. 5 or rotate from right to left awayfrom the latch plate 64 a, 64 a′ and toward the support posts 65 as thetarp 12 is rolled-up or furled on the roll bar member 18 and the topopening 7 a is uncovered and open (see also, FIG. 5).

In the most preferred embodiments of the present invention, selectivemovement of one arm 22 a is actuated by a motive source 30 having amotor 31. In preferred embodiments, the motor 31 will be either anelectric motor or a hydraulic motor, although other suitable motors mayalso be used. In the most preferred embodiments, the motor 31 will be aSuper Winch Power Drive (Model No. 719627 from Super Winch, Inc. ofPutnam, Conn.), which includes a worm gear (not shown) that drives theturning of the elongated roll bar member 18. As shown in FIG. 2A, themotor 31 can be attached to the sleeve 32 a and connected to anelectrical power source 33, as shown in FIG. 1, by electrical conduit34. It will be appreciated that other power sources may also be usedincluding, without limit, a truck battery (not shown) or a power takeoff (PTO) (not shown). Although it is within the scope of the presentinvention to provide a second motive source (not shown) to actuateselective movement of the roll bar member 18 from the back end 8 c ofthe truck box 6, in coordination with the selective movement of the rollbar member 18 actuated by the motor 31 associated with the arm 22 a onthe front end of the truck box 6, it is believed that a second motivesource is unnecessary to provide the necessary actuating assistanceneeded to either: 1) roll-up the tarp 12 as the roll bar member 18 movesin the roll-up direction; or 2) unroll the tarp 12 as the roll barmember 18 moves in the unroll direction and the tarp 12 is unrolled tocover the top opening 7 a. It will be appreciated that the selectivemovement of the roll bar member 18, in either the unroll or the roll-updirection, may be actuated by a hand crank of a type that is well knownin the art, including that disclosed in U.S. Pat. Nos. 4,505,512;5,823,067 and 6,135,534, the disclosures of which are herebyincorporated herein by reference (see also, FIG. 23). One of the greatadvantages of using a worm gear type motor, is the screw portion of theworm gear acts as a stop or lock against any un-rolling of the roll barmember when the roll bar member is motionless in any position,especially in the fully closed position, when the roll bar member issecured up against the latch plate 64 a. In that position, it isespecially important to maintain tension on the roll bar member 18 sothat it does not loosen up during transit and begin to flop around andbang against either the latch plate or the side of the truck box 6. Theworm gear type motor, which is preferred, significantly reduces thelikelihood that the roll bar member 18 will unroll and loosen withrespect to its engagement with the latch plate 64 a.

FIG. 2A also illustrates an upper or roll bar biasing member 50 ainterconnected to the arm 22 a. A second upper or roll bar biasingmember 50 b can be provided at the back end 8 c of truck box 6 andsecured to the second arm 22 b, for example, as shown in FIG. 3. Theupper biasing members 50 a, 50 b are provided in preferred embodimentsto assist the motive source 30 in moving the arms 22 a, 22 b, andindirectly the roll bar member 18, in the unroll direction or in otherwords, in a direction towards the second longitudinal side 8 b of thetruck box 6. The preferred upper biasing members 50 a, 50 b that areinterconnected to the arms 22 a, 22 b are preferably connected to thetruck box 6 with a retaining strap 70 on the longitudinal side 8 b oftruck box 6 as illustrated in FIG. 4 and extend along at least part of alongitudinal side 8 b of the truck box 6 and preferably to therespective arm 22 a, 22 b, where it is attached to the respective sleeve32 a, 32 b; or alternatively, the elongated roll bar member 18 as shownin FIG. 2B.

In order to prevent wear damage of the biasing members 50 a, 50 b, acorner guide 66 a, 66 b, 66 c is preferably provided. Each corner guide66 a, 66 b, 66 c includes a base 67 a and an orthogonally orientedflange 67 b. The base 67 a is provided with an aperture 67 c thatreceives a fastening element, and the flange, which extends outwardlyfrom the base, is provided with transverse slot 67 d that is incommunication with the aperture 67 c. A cord 58 may be connected to bycorner guide 66 a, 66 b, 66 c by passing it between arms formed by theslot 67 d and into the aperture 67 c. Preferably, the edges of theaperture 67 c are rounded and the surface of the aperture is providedwith a low-friction material. More preferably, corner guide 66 a, 66 b,66 c is plastic. The guide 66 a, 66 b, 66 c can be aligned eitherhorizontally (see FIG. 2A) or vertically aligned (see FIG. 2B).

FIG. 2B illustrates the upper biasing member 50 a somewhat differentlyconfigured as compared to FIGS. 1-2A. The upper biasing member 50 aextends through corner guide 66 c that is arranged such that thegenerally non-elastic or generally non-extendable cord 58 of the upperbiasing member 50 a passes through the corner guide 66 c and is directedgenerally perpendicular to the latch plate 64 a to where the upperbiasing member 50 a can be interconnected to the elongated roll barmember 18 with a rotatable collar 80 by way of a D-shaped ring 82, whichis attached to the collar and which extends radially therefrom.Alternate embodiments of the roll tarp assembly of the present inventioncan have one collar 80 at each end of the roll bar member 18 so that theroll bar member is tensioned at each of its respective ends. The collar80 can be arranged and configured such that it is easily and freelyrotatable about the elongated roll bar member 18 such that as theelongated roll bar member 18 rotates and moves over the upper surfaces25 of the respective end caps 8 e, 8 f at each end of the truck box 6,neither of the two respective generally non-elastic cords 58 will windaround the elongated roll bar member 18.

It will be appreciated that alternate embodiments of the roll-up tarpapparatus 10 may be configured to have one arm at each end of the truckbox 6, with each arm provided with a connecting member 44 a, 44 b thatis connected to opposing ends of the elongated roll bar member 18. Upperbiasing members 50 a, 50 b can be interconnected between the latch plate64 a or truck box 6 and one of the respective arms 22 a, 22 b, oralternatively, one of the respective ends of the elongated roll barmember 18. It will be appreciated that the respective upper biasingmembers 50 a, 50 b can also be attached to the respective arm 22 a, 22 bat one end and to the roll bar member 18 at the other end. Furthermore,in certain truck cargo box configurations, where the rear end of thetruck box opens, an arm at the rear end would likely interfere with theopening and closing operations. For that reason, and also because thecost of the additional arm may be a factor, arms at both ends areunnecessary and a single simple arm, preferably located at the front,may be provided and the rear end of the elongated roll bar member willbe connected to the latch plate or truck box with an upper biasingmember of the present invention or by other biasing members of the typethat have been disclosed in the prior art, e.g. the bungee cord engagedwith the roll bar member as disclosed in U.S. Pat. No. 4,505,512(Schmeichel), the disclosure of which is hereby incorporated herein byreference. Furthermore, it will be appreciated that the roll-up tarpassembly may be either motorized or manually driven. In the manuallydriven embodiment, power to the arm will be provided by a hand crank,similar to those now in use and publicly disclosed in the patentliterature and elsewhere (see, FIG. 23). It will be appreciated that acrank arm assembly or handle is relatively dissimilar to the arms of thepresent invention, insofar as it is not pivotally connected to the truckbox. In this regard, it will be further appreciated that the upperbiasing member of the present invention may be provided in yet anotheralternate embodiment in which the motive source is a hand crank and eachend of the elongated roll bar member is interconnected to the truck boxby a biasing member, either or both of which may be an upper biasingmember attached to a collar (see, for example, FIG. 2B) secured to theelongated roll bar member. In alternate embodiments, the cord can besecurely attached to the roll bar member such that the cord winds aroundthe elongated roll bar member as the tarp is opened and unwinds as thetarp is unwound (see, for example, FIG. 12A, 12B). In such embodiments,the arm can be a crank handle and it will not be pivotally connected tothe end of the truck box or trailer, but a biasing member of one type oranother will be provided. The biasing member may be an upper or roll barbiasing member of the present invention, preferably one interconnectedto the latch plate at each end of the roll bar member, but other biasingmembers and mechanisms that are well known in the art may also be used.

It will be further appreciated that various types of arms can be used.For example, hinged or biased arms can be utilized. Examples of sucharms are disclosed in U.S. Pat. No. 7,188,887 (Schmeichel), thedisclosure of which is herein incorporated by reference.

The upper biasing member 50 a, 50 b is preferably interconnecteddirectly to the respective arm 22 a, 22 b even more preferably, to thesleeve 32 a, 32 b of the respective arm 22 a, 22 b. In the preferredembodiment shown in FIG. 4, the upper biasing member 50 a includes anelastic member or cord 56. The elastic member or cord 56 is preferably astretch cord, bungee cord, shock cord, elastic rope or the like havingan extensibility of at least about 60% greater than its relaxed,unstressed state, more preferably at least about 80%, even morepreferably about 100%, and even more preferably at least about 130%.When the upper biasing member 50 a, 50 b is interconnected directly tothe respective arm 22 a, 22 b, the upper biasing member 50 a, 50 b willnot wrap around the elongated roll bar member 18. The sleeve 32 a, 32 bcan include a connecting ring 40 a, such that the upper biasing member50 a, 50 b can simply be clipped on to a sleeve 32 a, 32 b of therespective arm 22 a, 22 b with a clip 62, such as a carabineer or thelike. It will be appreciated that any other known connecting device maybe used as an alternative to the clip.

The rear arm 22 b is similar to the front arm 22 a as discussed herein,but is preferably interconnected to the elongated roll bar member 18with a connecting member 44 b. The connecting member 44 b is similar tosleeve 32 a of the first arm 22 a in that the connecting member 44 b isadjoined to the sleeve 32 b, which can slide along the shaft 36 b of thearm 22 b as the elongated roll bar member 18 is moved in the roll-up andunroll directions. FIG. 2A also illustrates an upper biasing member 50 ainterconnected to the arm 22 a. Preferably, a second upper biasingmember 50 b is additionally provided to assist the motive source 30 inmoving the rear arm 22 b in the unroll direction. The second upperbiasing member 50 b also is largely similar to the first upper biasingmember 50 a as previously discussed and is preferably connected to asecond retaining strap 70, just as illustrated in FIG. 4, which extendsalong at least part of a longitudinal side 8 b of the truck box 6 and tothe respective arm 22 b, or alternatively, the elongated roll bar member18. The second upper biasing member 50 b of FIG. 3 is preferablyinterconnected directly to the respective arm 22 b, even more preferablyto the sleeve 32 b of the respective arm 22 b. The sleeve 32 b caninclude a connecting ring 40 b, such that the upper biasing member 50 bcan simply be clipped on to the sleeve 32 b of the respective arm 22 bwith clip 62, such as a carabineer or the like.

In some preferred embodiments, the roll-up tarp assembly 10 will includeonly one arm 22 a located at the front end 8 a of the truck box 6 toaccommodate truck boxes 6 having a rear end 8 c that opens (notspecifically illustrated). In these embodiments, the rear upper biasingmember 50 b can be interconnected to the elongated roll bar member 18with the rotatable collar 80 similar to the arrangement andconfiguration illustrated in FIG. 2B.

Referring now also to FIG. 4, in preferred embodiments, the upperbiasing members 50 a, 50 b on each end of the truck box 6 will be twodifferent interconnected cords, one of which is an elastic cord 56 suchas a stretch cord, bungee cord, shock cord, elastic rope or the like andthe other of which is a generally non-elastic cord 58, which is joinedto the elastic cord 56 to form the two-piece biasing member 50 a, 50 b.In providing the two-piece biasing member 50 a, 50 b, the inventors haveconstructed and arranged the elastic cord 56 in such a way that theelastic portion 56 of the biasing member 50 a, 50 b is not required tostretch through the respective corner guide 66 a, 66 b, 66 c, whichwould be abrasive for the elastic cord 56, were it required to turn andstretch out toward the respective sleeve 32 a, 32 b, when the respectivearm 22 a, 22 b is moving in the roll-up direction and the roll barmember 18 is moving toward the support posts 65. In other words, thegenerally non-elastic portion 58 of the respective upper biasing member50 a, 50 b is preferably long enough and the elastic portion is shortenough such that the elastic portion 56 will not extend aroundrespective corner guide 66 a, 66 b, 66 c of the truck box 6 when theelongated roll bar member 18 is in the fully open position proximate thesupport posts 65. It will be appreciated that as either cord 56, 58passes through such a corner guide 66 a, 66 b, 66 c, in manycircumstances the cord will be required to pass over an edge, which willlikely abrade the cord, especially if it is an elastic cord such as abungee cord. Elastic cords are generally especially subject to wear asthey pass over hard edges, because they have an outer woven “skin” or“jacket.” The design of the jacket allows the elastic inner cord tostretch as the woven material of the jacket is draw straight to allowthe inner elastic cord material to stretch. The jacket is highly subjectto wear, however, and this is especially true for cords having greaterextensibility. So, when an elastic cord is drawn around a corner, theelastic cord is believed to be subject to high wear rates, requiringfrequent replacement.

The inventors have discovered that using elastic cords of diminishedsize, which are doubled, as opposed to one elastic cord that is twicethe size of the two cords, can provide a greater ratio of pull backforce provided by the doubled cord as compared to the force required topull the cord out, thereby enhancing the desirability of upper biasingmember when it is included the doubled elastic biasing cord as shown inFIG. 4. It will be appreciated that the doubling of the elastic cord inthis way also enhances the ability of the assembler to connect thegenerally non-elastic cord to the elastic cord, as well, because thedoubled cord provides a loop at its end, which is easy to tie to. Withrespect to the generally non-elastic cord 58, it has been discovered bythe inventors, and is believed but not relied upon, that a cord or ropeof a smaller diameter, which is also strong enough to bear the load thatit will be required to bear, will be more desirable as the generallynon-elastic portion 58 of the upper biasing member 50 a, because a greatportion of the biasing force of the elastic portion 56 of the upperbiasing member will actually be translated so as to place that biasingforce on the respective arm 22 a or roll bar member 18. It is believed,but is not relied upon, that because the smaller rope or cord will beexposed to less friction as it passes around a corner or over an edge,the biasing force of the elastic cord is not diminished as much as itmight be if the cord had a larger diameter. For this reason, the size ofthe generally non-elastic cord is preferably less than about ½ inch,preferably, less than about ¼ inch in diameter. In the most preferredembodiments, this cord will be about 3/16 of an inch, which is believedto diminish the loss of biasing force as the cord passes around thecorner or over the edge. It will be further appreciated that the elasticportion 56 of the upper biasing member 50 a may include a plurality ofelastic cords. While simply doubling the elastic cord 56 over to form adouble stranded elastic portion will be preferred, it will be furtherappreciated that it may also be desirable to have a plurality ofseparated elastic cords or two or more doubled elastic cords. Theelastic portion 56 of the upper biasing member 50 a may have any numberof elastic cords arranged in any configuration so as to provide aresilient elastic portion that will stretch and then place force againstthe ends, when the elastic portion is stretched.

Preferably a generally non-elastic cord 58, which is more resistant toabrasion, is interconnected with the elastic cord 56 so that thetwo-piece biasing member 50 a, 50 b has the attributes of both cordswhere these attributes are most useful. That is, the elastic portion 56provides extensibility and elasticity, but is not required to wraparound a corner or over an edge as it passes through a corner guide 66a, 66 b, 66 c. The generally non-elastic portion 58, which is moreresistant to abrasion than the elastic portion, is able to be drawnagainst the respective hard edges of the corner guides 66 a, 66 b, 66 cwhen the roll bar member 18 extends away from the latch plate 64 a. Thepreferred elastic cord will preferably have an extensibility of fromabout 40% to about 220% greater than its relaxed, unstressed state,preferably from about 60% to about 200%, more preferably from about 90%to about 170%, even more preferably from about 110% to about 150% andmost preferably about 130%.

It will be appreciated that the generally non-elastic cord 58 may be anycord that has very limited extensibility and may stretch slightly whenthe respective ends are drawn apart under at least some force. Theextensibility of the elastic cord 56 will generally be at least 10times, preferably at least 20 times, more preferably at least 30 timesas great as the limited extensibility of the generally non-elastic cord58, which may stretch somewhat, but will not be what is generallyrecognized to be an elastic cord. The generally non-elastic cord 58 maybe made out of a plurality of strands of natural material such as juteor the like, or a plurality of strands of polymeric rope making materialsuch as polyester, nylon or the like or even wire rope or cable. Metalrope or cable is not generally preferred, however, as it is notgenerally sufficiently flexible to allow the generally non-elastic cord58 to wrap around the hard edge of the corner guides 66 a, 66 b, 66 c ortruck box 6. In preferred embodiments the generally non-elastic cord 58will be made of a plurality of strands of polymeric material, woventogether to form the generally non-elastic rope or cord, preferablynylon polyester material. In preferred embodiments, the generallynon-elastic cord will have a hollow polyester braided jacket andpreferably a 3/16 inch polyester core, which may or may not be braided.

Upper biasing members 50 a, 50 b have respective first and second ends52, 54. As illustrated, each preferred upper biasing member 50 a, 50 bincludes an elastic member or cord 56 interconnected to a generallynon-elastic portion or cord 58. In this embodiment, a bungee cord 56 isinterconnected to a rope 58 made of a durable material, such as nylon(see also, above discussion regarding possible cords). Each upperbiasing member 50 a, 50 b is arranged and configured such that inoperation, the generally non-elastic portion 58 is the only portion ofthe upper biasing member 50 a, 50 b that contacts the edge of the truckbox 6, or corner guide 66 a, 66 b, 66 c located on the respective cornerof the truck box. The generally non-elastic portion 58 is more durablethan the elastic cord 56 and thus, can withstand more contact with therespective abrasive corner or corner guide 66 a, 66 b, 66 c. Asillustrated, the upper biasing members 50 a, 50 b can be supported alongthe truck box 6 with one or more respective support guides 68.

The first end 52 of each upper biasing member 50 a, 50 b is preferablyretained to the latch plate 64 a with one respective retaining strap 70that has a plurality of apertures (located behind knotted ends 60, seeFIG. 4). The ends 60 of the elastic cord 56 can be threaded through theapertures and secured by, for example, knotting cord ends 60.Additionally, grommets 76 are provided to reinforce the apertures, tostrengthen the strap proximate the apertures and to further support andsecure the knotted end 60 against the aperture. The retaining strap 70can be secured to the truck box 6 with a fastener 74. As illustrated inFIGS. 2A-2B and discussed above, a second end 54 of each respectiveupper biasing member 50 a, 50 b is preferably interconnected to therespective arm 22 a, 22 b (see also, FIG. 1). It will be appreciatedthat other mechanisms that are known in the art may be used to join therespective cords 56, 58 of the upper biasing members 50 a, 50 b and insecuring the biasing members 50 a, 50 b to the truck box 6.

It will be appreciated that a strap 70 material will be selected thatcan withstand the force placed on the attachment point by the biasingmember. It will be further appreciated that the retaining strap 70 isnot necessarily made of a flexible material and can be made out of arigid or semi-rigid material as stated above and that the grommet can bereplaced by a washer or the like. The retaining strap 70 is preferablymade of woven material; most preferably nylon polyester strap materialthat is determined to be strong enough to secure the respective upperbiasing member 50 a, 50 b to the truck box 6 without breaking, tearingor otherwise allowing the respective upper biasing member to disconnectfrom the truck box under normal use conditions. It will be appreciated,that other functionally suitable materials may be used in place of theretaining strap including without limit flexible, semi-rigid or evenrigid materials that will include a rigid metal plate.

FIG. 5 schematically illustrates the general movement of the front arm22 a as viewed from the front end 8 a (not shown in this figure forclarity) of the truck box 6. In preferred embodiments, the shaft 36 a,36 b of each arm 22 a, 22 b includes a restricting member 38 a such thatthe sleeve or sliding portion 32 a, 32 b of the arm 22 a, 22 b isprevented from traveling down the shaft 36 a, 36 b, past the respectiverestricting member 38 a. Restricting the movement of the sleeves 32 a,32 b downward along the shaft 36 a, 36 b is beneficial in that theelongated roll bar member 18, and thus the tarp 12, will be liftedsubstantially above apex A of the end caps 8 e, 8 f of the truck box 6and, as generally shown in FIG. 6A. Grain cargo is often crowned in thecenter, having a height highest towards the apex A of the end caps 8 e,8 f. As the elongated roll bar member 18 moves in the unroll directionaway from the support posts 65 and toward the latch plate 64 a, therestricting member 38 a associated with the shaft 36 a will prevent thesleeve 32 a, to which the motive source 30 and the elongated roll barmember 18 are attached, from sliding down the shaft 36 a as the arm 22 areaches the apex A of the end cap 8 e. This will have the effect ofraising the motive source 30 and the roll bar 18 up and over theaccumulated grain or other cargo C, gathered in the center of the truckbox 6 (see, for example, FIG. 6A), as the tarp 12 is unrolled to coverthe top opening 7 a (see, for example, FIGS. 7A and 7B). After the tarp12 is secured and the cargo C settles, spreading out more evenly withinthe truck box 6, the operator can re-secure the tarp 12 to insure atighter fit.

When the top opening 7 a is covered by the tarp 12 and the roll barmember 18 is secured against the underside of the latch plate 64 a, thetop opening 7 a is covered by the roll-up tarp apparatus 10. When theoperator wishes to expose the top opening 7 a when it is covered by thetarp 12, the operator will activate the motor 31 of the motive source 30so that the elongated roll bar member 18 will initially move down fromthe underside of the latch plate 64 a, until the tarp 12 is fullyunrolled and the roll bar member 18 will then continue to turn in thesame direction and begin rolling the tarp 12 up on the roll bar member18 in the opposite direction, initially climbing upward as it begins togather the tarp 12. As the roll bar member 18 continues to gather androll the tarp 12 up on its extended length, the roll bar member 18 willtraverse over the latch plate 64 a and then continue to gather or furlthe tarp 12 as the roll bar member 18 turns over the upper surfaces 25of the respective end caps 8 e, 8 f and moving in the roll-up direction.When the roll bar member 18 has gathered or furled all of the tarp 12 itis-positioned adjacent the nexus of the support posts 65 and the areawhere the tarp 12 is attached to the longitudinal side 8 d of the truckbox 6.

As illustrated schematically in FIGS. 7A, 7B and 13B, when the roll-uptarp apparatus 10 is moving in the unroll direction driven by the motivesource 30 (or, alternatively, a crank handle as shown in FIG. 23), theelongated roll bar member 18 will eventually traverse over the latchplate 64 a, 64 a′, and then travel down below the latch plate 64 a, 64a′ until the tarp 12, 12′ is fully unrolled. Preferably, the tarp 12,12′ is long enough such that the elongated roll bar 18 drops a length Lbetween about 5 to about 15 inches from below the highest point alongthe radius of the underside of the latch plate 64 d′, more preferablyabout 7 to about 13 inches, even more preferably about 9 to about 11inches, even more preferably about 10 inches. The long drop L allows theelongated roll bar member 18 to be secured underneath the latch plate 64a, 64 a′ even on a windy day, where the elongated roll bar member mightbow due to the wind. The center of the elongated roll bar member mayalso bow when a large load is loaded into the truck box 6 so that itinitially extends above the end caps 25 a in the middle before the loadsettles into the truck box 6. Once the tarp 12 is fully unrolled, theelongated roll bar member 18, still driven by the motor 31 of the motivesource 30, will roll-up in an upward direction gathering or rolling-upthe tarp 12 until the roll bar member 18 has gathered as much of thetarp 12 that is available within the space that is allowed and it issecured underneath the latch plate 64 a (see also, U.S. Pat. No.4,505,512 Schmeichel et al., the disclosure of which is herebyincorporated herein by reference).

The restricting members of the present invention may take many forms. Inpreferred embodiments, the shaft 36 a, 36 b of each arm 22 a, 22 b willinclude a plurality of adjustment apertures 29 a, 29 b. A preferredrestricting member, preferably a bolt 38 a, can be inserted transverselyinto one of the respective adjustment apertures 29 a, 29 b andinterconnected with a reciprocating nut 37 a, which, together, limit thedownward distance the sleeve 32 a, 32 b can slide on the respectiveshaft 36 a, 36 b.

Referring now also to FIG. 6B, an alternative restricting memberincludes a spring 42 that is placed above the respective restrictingmember 38 b to generally support the respective sleeve 32 a, and thusthe elongated roll bar member 18, above the cargo C in the truck box 6as the arms 22 a, 22 b direct the elongated roll bar member 18 in theroll-up and unroll directions. It will be understood that the spring 42of the present invention can be substituted with a variety of resilientmaterials.

FIGS. 6C-6E show alternative restricting member embodiments that can beused as a substitute for the restricting member 38 a illustrated inFIGS. 6A and 6B. The restricting member of FIG. 6C is a collar 38 csecured on the respective arm 22 a with a fastener 39 c. The restrictingmember of FIG. 6D is a pin 38 d inserted through one of a plurality ofapertures of the respective arm 22 a. The pin 38 d can be secured to therespective arm 22 a with a fastener 39 d. The restricting member of FIG.6E is a flattened portion 38 e of the respective shaft 36 a formed suchthat the sleeve 32 a cannot slide below the flattened portion 38 e. Itwill be understood that the restricting members disclosed are merelyillustrative and alternatives will be possible without departing fromthe spirit and scope of this disclosure.

FIG. 5 additionally illustrates how each upper biasing member 50 a, 50 bassists the movement of the respective arms 22 a, 22 b in the roll-updirection (only the first upper biasing member 50 a is shown but it willbe understood that second upper biasing member 50 b is arranged andconfigured similarly). When the respective arm 22 a is moving in therolled-up direction (from right to left, as shown in the figure), theupper biasing member 50 a is stretched and tensioned. As the motivesource 30 directs the arm 22 a in the unrolled position, the tensionedupper biasing member 50 a urges the arm 22 a to the other side 8 b ofthe truck box 6, thus assisting the motive source 30. FIG. 5 furtherillustrates, in phantom, the elongated roll bar member 18 in an openposition, wherein the elongated roll bar member 18 has completelyrolled-up the flexible cover 12 and the elongated roll bar member 18 andthe gathered tarp 12 is rolled up against the plurality of support posts65 extending along the longitudinal side 8 d of the truck box 6,opposite the latch plate 64 a (see also, FIG. 1).

Referring now also to FIGS. 9 and 10 that illustrate an alternative andpreferred method of securing at least one respective arm 22 a′ to therespective side 8 a, 8 c of the truck box 6 with a bracket or the like90, 90′. As shown, a bottom end 26 a′ of the arm 22 a′ preferablyincludes a retaining element or connecting portion 27′ having a socketthat corresponds to a ball 93. The ball 93 is provided with a threadedstem that is interconnected to the support member 94. The correspondingconnecting portion 27′ and ball 93 collectively form a ball joint 95 toallow for minor adjustments of the longitudinal placement of the top ofthe respective arm 22 a′ as best illustrated in FIG. 10. The preferredallowed range of movement is at least about 5 degrees, preferably atleast about 10 degrees, more preferably at least about 15 degrees andmost preferably at least about 20 degrees such that the roll-up tarpapparatus 10 can be effectively used with truck beds having a variety oflengths. For example, if the elongated roll bar member 18 is longer thanmight be needed, the ball joint 95 will allow for the longer roll bar18. Moreover, the ball joint 95 is preferred for truck boxes havingslanted ends 8 c′ (as shown in phantom in FIG. 10), where it is likelythat the arm 22 a′ will have to slant back toward the top of an end cap(see also, FIG. 2A) over the top opening 7 a of the truck box 6. It willbe appreciated that such slanted back truck boxes allow haulers to carrymore cargo lower to the center of gravity of the trailer and alsoprovide a preferred climbing angle for a hauler wanting to climb up aladder at the back of the truck box to inspect the cargo load in thetruck box.

In alternate preferred embodiments, each respective arm 22 a, 22 b isadditionally biased with a lower biasing member 100 as best illustratedin FIGS. 1 and 8, preferably one lower biasing member 100 operativelyengaged with each arm 22 a, 22 b. As illustrated most clearly in FIG. 8,preferably one of the respective arms 22 a, 22 b, in this illustrationfront arm 22 a, is interconnected to the respective side 8 a of thetruck box 6 with a mounting bracket 90. The mounting bracket 90 includesopposing feet 91 a with apertures for receiving fastening elements, anda raised section 91 b that is spaced outwardly from the side 8 a of thetruck box 6 when the mounting bracket is attached to the truck box.Extending from the raised section 91 b of the mounting bracket 90 is asupport member 92 to which one arm 22 a can be rotatably mounted. Inthis embodiment, the bottom end 26 a of the arm 22 a includes analternate retaining element 27 configured to be a transverse cylindricalportion that can be connected to the support member 92. The preferredlower biasing member 100 includes a torsion spring 102 positioned on thesupport member 92 between the mounting bracket 90 and respective arm 22a. Preferably, a first nut 94 is welded to the support member 92, whichis threaded on both ends. The cylindrical retaining portion 27 of thearm 22 a can be slid over the support member 92 and secured thereto by asecond nut 96. The lower biasing member 100 having an assisting end orarm 104 with a finger 105 and a static or stationary end 106, with thebiasing member 100 arranged and configured such that the lower biasingmember will assist the motor 31 of the motive source 30 (see also, FIG.2A) by applying a force F to the arm 22 a so that the arm 22 a is alwaysurged in the direction of side 8 b of the truck box 6. The mountingbracket 90 preferably includes a stop, a block 98 or similar device tomaintain the position of the static or stationary end 106. Asillustrated, the finger 105 of the preferred assisting end 104 engagesthe respective arm 22 a and pushes the respective arm 22 a in the unrolldirection. It will be understood that a lower biasing member 100,located proximate the bottom end 26 a of the arm 22 a, can be used inconjunction with or as an alternative to the upper biasing member 50 alocated towards the top end 24 a of the respective arm 22 a. A similarlower biasing member is preferably operatively secured to the second arm22 b.

In an alternate preferred roll-up tarp apparatus 110, as generallyillustrated in FIGS. 11-16C operatively connected to a truck box 6, theroll bar biasing member 150 includes a cord 158 having first and secondends 160, 162, one end 162 is interconnected to the elongated roll barmember 18 and the other end 160 is interconnected to a tensioningelement 156, such as a spring, which in turn, is interconnected to thetruck box 6. Preferably, one roll bar biasing member 150 is attached toeach end of the elongated roll bar member 18 although only one is shownfor clarity. The preferred tensioning element 156 is a metallic coilspring, versus, for example, an elastic cord, because it is believedthat springs generally work better when it is generally at or belowfreezing and/or there is frost and/or snow on the tarp and/or spring.The inventors have found that the elasticity (or stretchability) of anelastic cord is generally more affected by cold temperatures incomparison to a metallic coil spring. For example, a cold bungee cordwill typically lose a significant amount of its elasticity in very coldweather whereas a spring generally will not. The tensioning member 156is preferably a spring but can be at least one elastic cord or the likehaving an extensibility of at least about 60% greater that its relaxed,unstressed state, more preferably at least about 100%, even morepreferably at least about 130%. One preferred spring is made of musicwire or the like having a wire diameter of about 0.148″, an outside coildiameter of about 1.50″, free length of about 14.0″, a spring rate ofabout 3.6 lbs. per inch, an initial tension of about 10 lbs., a maximumload of about 92 lbs., a maximum deflection of about 23″ and a zinc PLfinish or the like.

Biasing member 150 is connected to one longitudinal side 8 b of thetruck box 6 such that an unwound portion of the cord 158 and thetensioning element 156 remain generally perpendicular to the elongatedroll bar or roll tube 18 during operation. This perpendicularrelationship provides for a generally self-adjusting and self-aligningroll bar biasing member in that the unwound portion of the cord 158 willhave the tendency to remain generally perpendicular to the elongatedroll bar member 18 as the cord 158 is continually tensioned in thedirection of the longitudinal side 8 b of the truck box for which thebiasing member 150 is secured. Generally, the unwound portion of therespective cord 158 of the respective biasing member 150 remainsperpendicular to the elongated roll bar member 18 because of theconstant tension exerted on the cord 158. Therefore, the tension exertedon the respective ends of the elongated roll bar member 18 will begenerally equal and provide for generally even movement of the ends ofthe roll bar member. When the cord 158 is being unwound from theelongated roll bar member 18, as the roll bar member moves from theclosed position to a fully open position in which the flexible cover ortarp 12 is fully wound up upon the elongated roll bar member 18, theforce on the cord generally increases and the spring 156 stretches. Asthe cord unwinds as the elongated roll bar member 18 is on the top ofthe truck box 6, rolling along support bars 9 and the ridges of therespective end caps 25 a along the edges of the end caps, the cord 158actually unwinds slower than the tarp 12 gathers or winds up on the rollbar member 18, especially as the tarp thickness on the roll bar 18begins to grow in thickness, because the cord tends to be gathereddirectly on the outer surface of the roll bar 18, whereas the thicknessof the tarp, as it becomes rolled up upon the roll bar, makes thediameter of the surface upon which the tarp 12 is wound, increasinglygreater than the diameter of the roll bar 18 proximate the area wherethe cord 158 is gathered. For this reason, the cord 158 has to slideover the top 25 of the end cap 8 e proximate the roll bar member 18 andover an edge 64 f′ of the latch plate 64 a in the direction of the rollbar member, even as the spring 156 is being stretched and the force onthe cord 158 is being increased, because the cord 158 is being releasedfrom the roll bar member 18 at a slower rate than the linear length ofthe tarp 12 is being gathered or wound up on the roll bar member 18 andat a slower rate than the roll bar member 18 is moving over the topopening 7 a of the truck box 6. When the tarp 12 is being unwound fromthe roll bar member 18, and the roll bar member is moving from an openposition toward a closed position, the tarp 12 is released or unwoundfaster than the cord 158 is wound up on the roll bar member 18, so, inthat case the cord 158 will again slide over the top 25 of the end cap 8e and over an edge 64 f′ of the latch plate 64 a, but in this case itwill be releasing the stress on the spring 156 and sliding back towardthe latch plate 64 a.

While the biasing member 150 may be connected directly to the truck boxside 8 b, connection via an attachment plate 270 is preferred. Onepreferred attachment plate 270 includes a base 271 and an extension 272that is angled with respect to the base 271. The base 271 includes anaperture 273 for receiving a fastener 274 that is used to secure theattachment plate 270 to the truck box side 8 b. The extension 272, whichpositions the biasing member 150 away from the surface of the truck boxside 8 b, includes a slot or channel 275 that is in communication with atensioning element receiving section 276 having at least one securingridge 278 with a plurality of serrations. Preferably, the tensioningelement 156 is a spring having a portion that can be inserted into theslot or channel 275, moved toward the receiving section 276 and thenretained at one of the serrations of the securing ridge 278. It isadvantageous to provide a plurality of serrations along the securingridge 278 so that the position of the tensioning element 156 can beadjusted and less care needs to be taken when locating the properposition in which to secure the attachment plate 270 to the side of thetruck box 8 b.

One roll-up tarp apparatus 110 further includes a protective bumper 268or the like attached to the side 8 b of the truck box 6 proximate thelatch plate 64 a, 64 a′ and extending downwardly towards attachmentplate 270. The bumper 268 primarily serves to protect the side 8 b fromthe biasing member 150, which, under tension, can be snapped against theside 8 b of the truck box 6 and cause damage. The bumper 268 can alsoprotect the side 8 b from the roll up tarp apparatus 110 that isimproperly secured and which may swing up against the side 8 b.Preferably, the bumper 268 is provided with a somewhat resilient surfaceso that it is able to protect an errant biasing member 150 or elongatedroll bar member 18 from damage as well. See, for example, see FIG. 11.In addition, preferred biasing members 150 may be provided with asheathing or shroud 164 to protect the tensioning element 156 fromdebris or the like. Preferably, the sheathing is in the form of aflexible sheet of material with two lateral edges and two longitudinaledges. The longitudinal edges can include complimentary fasteners, suchas hooks 166 and loops 168, so that the sheathing can easily be securedaround and removed from the tensioning element 156 without having toremove the tensioning element from the attachment plate 270.

With respect to the roll-up tarp apparatus 110 of FIGS. 11-16C, thegeneral tension exerted by the biasing member on the elongated roll barmember 18 is not constant as the elongated roll bar member rolls orunrolls the flexible cover 12. As is shown in FIG. 18A and the graphdepicted in FIG. 22 a (see also Table 1), tension exerted on theelongated roll bar member 18 at the completely secured position (P1) andat the completely open position (P6) is about equal (within about 1lb.). In addition, it is noted that in this embodiment there iscontinual tension placed on the elongated roll bar member 18 when theroll bar member is in intermediate, partially-open positions (P4-P5) orpartially closed positions (P2-P3) and even when the elongated roll barmember is in the secured or latched position (P1) as is also illustratedin FIG. 16C. Continual tension exerted on the elongated roll bar member18 when the roll bar member is in the secured or latched position isadvantageous because it has been discovered that it will substantiallyeliminate lateral swinging of the elongated roll bar member. This, inturn, can prevent damage from the elongated roll bar member bypreventing it from repetitively banging against the respective side 8 bof the truck box 6. In addition, if continual tension is exerted on theelongated roll bar member 18, there is a reduced risk that wind gustscould infiltrate under the flexible tarp 12 and lift the tarp up,similar to a sail. This can be a significant problem as wind lifting thetarp 12 up could potentially blow the tarp off of the truck box 6 orotherwise damage the roll up tarp apparatus. Since grain trucks areoften used in the plains of the Midwest, where gusty winds are common,the present invention provides a significant advantage as compared toknown devices that do not address this problem. It is noted that theamount of tension noted in Table 1, which is illustrated in the graph ofFIG. 22 a is simply an example, and that the actual amount of forceexerted by a tensioning element can differ based on the particulartensioning element selected as well as the configuration of the roll-uptarp apparatus (see also, FIG. 22 b).

It will be appreciated that alternate roll-up tarp apparatuses may havea tension pattern more similar to what is illustrated in FIG. 22 b. Toacquire the data illustrated in FIG. 22 b, a roll-up tarp apparatus wasoperatively secured to a truck box. The roll-up tarp apparatus wassimilar to that shown in FIG. 11 and included a biasing member having aspring made of music wire having a wire diameter of 0.148″, an outsidecoil diameter of 1.50″, a free length of 14.0″, a spring rate of 3.6lbs. per inch, an initial tension of 10 lbs., a maximum load of 92 lbs.,a maximum deflection of 23 in. and a zinc PL finish. The roll-up tarpassembly was operated to open the cover from a secured position P1. Ateach position (P1-P6) illustrated in FIG. 18A, the movement of theelongated roll bar member 18 was stopped and the length of the springwas measured to indicate the amount of stretch. The various stretchlengths are listed in Table 2 below. Then, to determine the amount oftensioning force exerted by the spring, a pull type scale, preferably aCabela's Buck Scale (Item No. XJ-226597), was attached to the spring andthe spring was stretched to correspond to the length of the springmeasured during operation of the roll-up tarp apparatus. Once the lengthof the spring equaled that measured during operation of the roll-up tarpapparatus, the pounds of tensioning force indicated on the scale wererecorded and the recorded force is listed in Table 2 below. It is notedthat the highest amount of tensioning force exerted by the tensioningelement (spring) in both FIGS. 22 a and 22 b is highest when theelongated roll bar member is in the secured position and the openposition.

TABLE 1 Corresponding Tensioning Force Position (lbs.) P1 54 P2 18 P3 20P4 25 P5 35 P6 55

TABLE 2 Corresponding Length of Spring Tensioning Force Position (in.)(lbs.) P1 40 235 P2 15.5 66 P3 15.5 66 P4 17 77 P5 20 98 P6 28 155

As with previous embodiments, when the roll-up tarp apparatus 110 ismoving in the unroll direction driven by the motive source 30 (or,alternatively, a crank handle), the elongated roll bar member 18 willeventually traverse over the latch plate 64 a′, and then travel downbelow the latch plate 64 a′ until the tarp 12 is fully unrolled. Oncethe tarp 12 is fully unrolled in an unrolled position (P2), theelongated roll bar member 18 can be rolled-up in an upward direction,gathering or rolling-up the tarp 12 until the roll bar 18 has gatheredas much of the tarp 12 that is available within the space that isallowed until the roll bar member 18 and the tarp 12 rolled up on theroll bar member 18 engage the latch plate 64 a′ so that the roll barmember 18 is pressed up against the latch plate 64 a′, with the gatheredportion of the tarp being “sandwiched” in between, and the roll barmember 18 is fully secured underneath the latch plate 64 a′ in theclosed or fully secured position (P1). When the tarp 12 is fullyunrolled and then is moving upward to be secured underneath the latchplate 64 a′, as shown in FIG. 16C, the cord 158 and the flexible cover12 are both being wound around the elongated roll bar member 18 in thesame direction with respect to the rotational movement of the elongatedroll bar member 18. When the roll bar member 18 is turned to allow thetarp 12 that is wound up on the roll bar member and a portion of thecord 158 that is wound up on the roll bar member to be unwound, as theroll bar member 18 moves from the fully closed or secured position (P1)to the “unwound” position (P2) shown in FIG. 13 and schematically inFIG. 18A, the tension on the roll bar member 18, exerted by therespective biasing elements at each of the respective ends of the rollbar member 18, is the least that it will be at any point in the movementof the roll bar member 18, i.e. from the fully closed position (P1) tothe fully open position (P6). In this unwound position (P2), the tensionon the each end of the roll bar member 18 is preferably preset so as tomaintain sufficient tension to prevent the roll bar member 18 fromstriking the side of the truck box 6 and/or prevent the roll bar member18 from being carried upwards over the top of the truck box 6 by a gustof wind that catches the underside of the unwound tarp 12, so that theroll bar member is pulled up and over the truck box. When the elongatedroll bar member 18 is in the fully unrolled position (P2), if the rollbar member 18, as shown in FIG. 16B, turns in a clockwise direction asviewed from the front of the truck box 6, the tarp 12 will wind-up onthe roll bar member 18 and the cord 158 will also wind-up on the rollbar member 18 as the roll bar member 18 moves toward the closed or fullysecured position (P1). When the roll bar member 18 is in the fullyunrolled position (P2) and the roll bar member 18 is turned in theopposite direction (counterclockwise direction), the winding directionof the tarp will change. As the tarp 12 begins to be wound in the otherdirection and the roll bar member 18 moves from the unwound position(P2) to the initial wind-up position (P3), shown schematically in FIG.18A, the tarp begins to wind-up on the roll bar member 18, but the cord158 continues to be released from and unwound from the roll bar member18. As the elongated roll bar member 18 moves over the top 7 of thetruck box 6, toward the fully open position (P6), shown schematically inFIG. 18A, the cord 158 is unwinding and the flexible tarp 12 is windingup with respect to the rotational movement of the elongated roll barmember. It will be further appreciated that when the roll bar member 18moves from the fully open position (P6), shown schematically in FIG.18A, to the initial wind-up position (P3), shown schematically in FIG.18A, the cord 158 will wind-up on the roll bar member 18 and theflexible cover 12 will unwind from the elongated roll bar member 18.Because the outer diameter of the wound up tarp on the roll bar member18 is greater than the diameter of the part of the roll bar memberproximate the area where the cord 158 is wound up when the roll barmember 18 is in the open position (P6), it is believed that the cord 158is wound up on the roll bar member 18 at a linear rate that is less thanthe linear rate of the release or unwinding of the rolled up portion ofthe tarp 12 until the roll bar member 18 begins to get close to the sideof the trailer 6 where the latch plate 64 a′ is located, which causesthe respective cords 158 at each end of the respective roll bar member18 to slide over the tops 25 of the respective end caps 8 e, 8 f and therespective edges of the latch plate 64 a′. When the roll bar member 18is moving toward the fully open position (P6) from the initial wind-upposition (P3), the cord 158 will slide over the respective tops 25 ofthe respective end caps 8 e, 8 f, toward the other side of the truck box6, where the roll bar member 18 will rest when it is in the fully openposition (P6), because the tarp 12 will gradually effectively increasethe diameter of the rolled-up tarp 12 on the roll bar with respect tothe diameter of the portion of the roll bar member 18 where the cord 158is unwound, as the tarp 12 is so gathered.

It is noted that the cord 158 winds-up around the outer tube 19 b of theelongated roll bar member 18, preferably not around a spool. Unlike rolltarp apparatuses, where the cord winds-up around a spool, the cord 158generally rolls and is gathered flat on the roll bar member andgenerally does not gather upon itself as the cord winds around theelongated roll bar member 18. It is also noted that the cord 158 isgathered on and released from a portion of the roll bar member 18 thatdoes not extend beyond the end cap 8 e, 8 f on either end of the trailer6. It is believed, but not relied upon, that when the cord 158 winds-uparound the outer tube 19 b over the end cap 8 e, 8 f, as opposed tobeing wound around a spool or the like that extends out beyond the endcap on either end of the trailer, it is safer because the cord cannotcatch on any ladder or other devices positioned on the ends of the truckbox or get in the way of dump gates, doors or the like. Moreover, thecord is further out of the way and protected from passing trees andother objects. Additionally, the cord preferably winds such that thecord does not overlap itself and winds-up in the direction of the tarp(see, for example, FIGS. 12A, 12B), when the roll bar member 18 is goingfrom the unwound position (P2) to the secured position (P1). When spoolsare used, they are generally used on the end of an elongated roll barthat extends out beyond the end caps so that the cord or cable is outand away from the front or back of the trailer where it can easily beeither in the way of other operations or become engaged with passingobjects.

Now also referring to FIGS. 18B-18C, it will be understood that biasingmembers 150′, 150″ and 150′″ may be configured such that they are atleast partially located within the truck box 6. Typical truck boxes 6include a supportive frame 6 a including a skin or shell 6 b securedthereto. Inside the truck box 6 is a hopper 6 c. In various embodiments,a tensioning element 156′, 156″, 156′″ of the respective biasing member150′, 150″, 150′″ can be secured to a portion of the frame 6 a and therespective cord 158′, 158″, 158′″ can extend out of the truck box 6 viaan aperture 6 d in the shell 6 b. Preferably, the aperture 6 d includesa grommet 170 to reduce wear on the cord 158′, 158″, 158′″ and can serveto guide the cord to the elongated roll bar member 18. As shown, thebiasing member 150′, 150″, 150′″ can be secured to the frame 6 a at avariety of angles with respect to the side 8 d of the truck box 6.

As best illustrated in FIGS. 12A, 13A and 24-29, the elongated roll barmember 18 preferably includes an inner tube 19 a, an outer tube 19 bhaving an outwardly opening longitudinal channel 19 c that is incommunication with an larger longitudinal channel 19 d, and spacerelements 19 e that position the inner tube 19 a within the outer tube 19b. The spacer elements 19 e can be secured to the outer tube 19 b with ascrew fastener 19 f or the like. Preferably, the inner tube 19 a servesas an attachment point for the motive source 30 or coupling 323 (furtherdiscussed below), and to facilitate the connection between the tube 19 aand the motive source the tube 19 a may project beyond the end of theouter tube 19 b. In preferred embodiments, the flexible cover 12 isprovided with an enlarged longitudinal bead that is removably positionedwithin the longitudinal channel 19 d by feeding the bead into an openend of the channel 19 d and sliding the rest of the cover 12 along thechannel 19 c. In further preferred embodiments, as further discussedbelow, a cord 258 of a biasing member 250 is secured to and unwraps fromaround the outer tube 19 a as the elongated roll bar member 18 movesinto the open position. More specifically, it is important to note thatthe cord of the biasing member and the flexible tarp are arranged sothat they wind about the elongated roll bar member in oppositedirections. Thus, for example, as the roll-up tarp assembly 110 is movedfrom the open position toward the secured or latched position, the tarpis unrolled or unfurled as the cord 158 of the biasing member 150 isbeing wound about the roll bar. Conversely, as the roll bar 18 is movedfrom the secured position toward the open position, the cord 158 of thebiasing member 150 is unwound from the roll bar as the tarp 12 is beingrolled-up or furled about the roll bar. It is also important todistinguish how the tarp 12 and the cord 158 of the biasing member 150wind about the roll bar 18. As the tarp assembly 110 is moved betweenthe open and secured positions, the cord 158 of the biasing member 150winds preferably about the roll bar 18 in a spiral or helical manner,while the tarp 12 winds upon itself and its circumference changes. Whenthe tarp 12 rolls upon itself, it also may roll upon portions of thesupport bars or ribs 9 and/or the upper surface 25 end caps 8 e, 8 f. Itwill be appreciated that the roll bar 18 circumference increases as theroll bar moves from a position just above the latch plate 64 a, 64 a′adjacent the second longitudinal side 8 b to the open position adjacentthe first longitudinal side 8 d. As the roll bar 18 moves from thesecond longitudinal side 8 b to the first longitudinal side 8 d, thecircumference of the rolled-up tarp 12 becomes significantly larger thanthe roll bar 18, while the cord 158 unwinds at a constant rate. Thiscreates a distance differential that results in an increase in tensionin the cord 158 as the elongated roll bar member 18 and the tarp 12 aremoved to the open position. This increased tension is accommodated bythe tensioning or spring element 156 of the biasing member 150. When theelongated roll bar member 18 is moved past the latch plate 64 a′ andallowed to continue to unroll until it bottoms out tension is at aminimum. However, as the roll bar 18 continues to rotate in the samedirection, the tarp 12 is rolled up against the latch plate 64 a′ andthe force exerted by the tensioning member 156 increases. As it turnsout, the forces exerted by the biasing member 150 when the roll up tarpassembly 110 is in either the open or secured positions are roughly thesame, while the force exerted by the tensioning member 156 when theelongated roll bar member 18 is located between the longitudinal sides 8b, 8 d of the truck box 6 will be less than the tensioning forces whenthe elongated roll bar member 18 is in either the open or securedposition.

Now also referring to FIGS. 12B and 13B illustrating an alternativeflexible tarp 12′ that is secured within the channel 19 c of theelongated roll bar member 18. FIGS. 12B and 13B further illustrate howcord 159 can be secured into channel 19 c by tying a knot 163 in cord150 and then sliding the knot into the channel. Knot 163 may bepreferred over the screw illustrated in FIG. 12A because the knot 163can be readjusted as desired. Such adjustments are easily made when theroll bar member 18 is in the unwound position (P2), when the tension onthe cord 158, created by the biasing element 256, is the least that itwill be at any point in the transition from the fully open position (P6)to the fully secured position (P1).

An alternate roll-up tarp apparatus 210 having a roll bar biasing member250 is generally illustrated in FIGS. 17A-17C. In this illustratedembodiment, the roll bar biasing member 250 is operatively secured tothe truck box 6 and includes a cord 258 interconnected to a tensioningelement or spring 256 with a clip 264 and a pulley 266. One end 260 ofthe cord 258 is preferably interconnected to the latch plate 64 a′ and asecond end 262 is interconnected to the elongated roll bar member 18,for example, by drilling a hole through the external surface of theouter tube 19 b of the elongated roll bar member 18, extending the cordthrough the hole and tying a retaining knot in the end 262 of the cord258 (another option in which the cord is connected to the elongated rollbar member with a screw is illustrated in FIGS. 12-13). In furtherembodiments (not shown), a knot can be tied in the end of the cord, andthe knot can be slipped into the channel 9 c and the pulled tight tosecure. This roll bar biasing member 250 is generally less preferred formotorized roll-up tarp apparatuses as it requires about two times thelength of cord 258 to stretch the tensioning element or spring 256 ascompared to an embodiment utilizing a cord directly connected to thetensioning element as discussed herein. Utilizing a pulley 266 isoccasionally preferred, especially when the roll-up tarp apparatus isinstalled on a trailer 6 having a shorter sidewall. For roll-up tarpapparatuses utilizing a crank arm (see also, FIG. 23), the pulleyreduces the amount of force needed to operate the crank arm 400. Inessence, when turning the crank arm 400 to position the elongated rollbar member 18 into the secured position, the pulley 266 will requirethat the spring 256 be stretched half as much than if the cord 258 wasdirectly attached to the spring 256, thereby making it easier to movethe elongated roll bar member 18 against the bias of the spring 156. Itis further believed that this embodiment may have additional safetyfeatures, in that the spring 156 is not stretched significantly inoperation, as would be the case if a pulley 266 was not used. The pulley266 allows for easier rolling up of the tarp 12 without overstretchingthe spring 256. It is believed, but not relied upon, that the roll-uptarp apparatus 210 applies forces to the elongated roll bar member 18generally as illustrated in FIG. 22. In alternate embodiments (notshown), multiple pulleys may be used in series to simplify or ease theturning of such a crank arm and/or the cord 158 can be bolted to a sideof the truck box 6 or the latch plate 64 a.

Preferably, a second roll bar biasing member (not shown) is additionallyprovided at the rear end of the elongated roll bar member 18 to assistthe motive source 30 in moving the rear end of the elongated roll barmember 18 in the unroll direction uniformly. The second roll bar biasingmember is preferably identical to the first roll bar biasing member 250and is provided so that there is generally uniform tension on theelongated roll bar member 18. The rear biasing member can be connectedto the elongated roll bar member 18 in the same manner as the first rollbar biasing member 250 as discussed above.

Preferably, the roll-up tarp assemblies 110, 210 of the presentinvention are arranged and configured such that a substantial portion ofthe wound-up cords 158, 258 are stowed underneath the latch plate 64 a′when the elongated roll bar member 18 is in the latched, securedposition (P1). In preferred embodiments, the cord 158, 258 winds aroundthe elongated roll bar member 18 and the wound up portion has athickness generally no greater than the thickness of the tarp 12 suchthat the elongated roll bar member 18 can fit snugly under thedownwardly facing curved or arcuate surface 64 d, 64 d′ of latch plate64 a, 64 a′ as illustrated (see, for example, FIGS. 7B, 12 and 16C).When the elongated roll bar member 18 is in the secured position, thetarp 12 is wrapped around the elongated roll bar; the thickness of thetarp will be greater than the thickness of the cord that wrapped aroundthe roll bar member. This separation takes pressure off of the cord thatwould otherwise exist if the cord was thicker than the tarp materialgathered around the roll bar 18 proximate the respective ends of theroll bar 18. In a preferred embodiment (not shown), a webbing material,such as the type of material used to make seat belts for motor vehiclesand the like, is sewn into the edge of the tarp 12, thus providing greatthickness to the respective edges of the tarp 12 in the area where thisthickness is helpful to provide separation from the latch plate 64 aproximate to the portion of the cord 158 that is wound up around theroll bar member 18, when the roll bar is in the secured position (P1).This will significantly reduce the likelihood that the cord 158, 258might be worn or abraded by coming into contact with the bottom surfaceof the latch plate 64 a.

The cord 158, 258 may be made out of a plurality of woven strands ofnatural material such as jute or the like, or a plurality of strands ofpolymeric rope making material such as polyester, nylon or the like oreven wire ropes or cables. In preferred embodiments, the generallynon-elastic cord will be a nylon polyester braided cord, preferably a3/16 inch nylon polyester braided cord. With synthetic materials, thecord preferably includes a jacket surrounding an inner cord. Preferably,the inner cord is polyester material and the jacket is made of nylonmaterial. Alternatively, KEVLAR® para-aramid synthetic cords can be usedas the inner cord in conjunction with a polyester or nylon jacket, forexample. Para-aramid synthetic cord and the like are preferred becausethey generally do not stretch over time. Metal rope and cables are notgenerally preferred, however, as they are not generally flexible enoughto allow the generally non-elastic cord to slide around the edges of thetruck box. In addition, a metal rope and cables are generally moreabrasive and can mar surfaces. For embodiments in which a jacket issecured over the inner cord, black is the preferred color for the jacketbecause it is believed that black will best prevent ultraviolet raysfrom damaging the inner cord.

The decision to include one or two arms as well as the decision toinclude what type and location of biasing members is largelycustomizable. If the roll-up tarp apparatus is to only have one arm, itis preferred that the arm be located on the front end of the truck boxto accommodate rear opening style ends as previously discussed. It maybe desirable to eliminate any sort of arm or biasing member on the frontside of the truck box so that ladders can be more easily positionedproximate the front end of the truck box. Embodiments of the presentinvention further include an upper biasing member secured to the frontarm and a lower biasing member connected to the second, rear arm. Inaddition, the front arm may include an upper biasing member as well as alower biasing member, wherein the rear arm could be omitted and theelongated roll bar member could be additionally biased with an upperbiasing member secured to the elongated roll bar member with a rotatablecollar or the like. Alternatively, only upper or only lower biasingmembers can be utilized. The number of potential combinations ofelements of the present invention is virtually limitless and all can beutilized as desired to create a product embodying characteristicsdesired for the specific product and purpose. All such combinations areconsidered within the scope of the invention.

Elongated roll bar members 18 can have a variety of diameters. Inpreferred embodiments, the elongated roll bar member 18 has a diameterof about three inches. In alternate embodiments, the elongated roll barmember 18 can have a diameter of two inches, more or less. Preferably,the elongated roll bar member 18 has a diameter of about three inches asthe inventors have found that this larger elongated roll bar member isless prone to bending or bowing and will remain straighter as theflexible cover is rolled-up and unrolled. In addition, it is believedthat a roll bar having a diameter of about three inches will be moreable to resist wind and gravitational forces than a smaller diameterelongated roll bar member. Moreover, it is believed that a largerdiameter roll bar member 18 will be able to provide for a straighter andmore uniform roll-up of the flexible cover 12.

For elongated roll bar members 18 having a larger diameter, for examplea diameter of about three inches or more, the motive source 30 ispreferably interconnected to a converter unit 300 that allows the motor31 to provide more torque to the roll bar member 18, as opposed tohaving to use a more powerful motor (see, for example, FIGS. 19-21).Generally, the converter unit or unit 300 will be a force multipliersuch as a chain drive, a gear box, a V-belt drive system or the likethat multiplies the force provided by the motor 31. The converter unit300 is preferably connected to the second or top end 24 a of the arm 22a, and includes a shaft 322 that is connectable to the elongated rollbar member 18 with a coupler 323. More specifically, one preferredconverter unit 300 shown in FIG. 19 includes a u-shaped frame or housing302 with an input section 304 and an output section 306, with thehousing including two side walls 308, 310 connected to each other by aweb 312, with the side walls supporting first and second parallel shafts320, 322 at respective input and output sections 304, 306. In furtherembodiments, the housing 302 is fully enclosed. The housing 302 ispreferably small as a smaller housing will generally have a lowerweight. The first and second shafts 320, 322 are rotatably supported bybearing elements 324, and each shaft 320, 322 supports a wheel 326, 328,respectively. The wheels 326, 328, which are preferably located betweenthe side walls of the housing 302, are spaced apart from each other andwhich are connected to each other by an the endless belt 330, which isalso preferably located between the side walls 308, 310 of the housing.Preferably, the wheels 326, 328 are sprockets and the endless belt is achain 330 that engages teeth 327, 329, respectively, of sprockets 326,328. The first wheel or sprocket 326, attached to the first shaft 320,is operatively connected to the motor 31, which can also be attached tothe housing 302. The second wheel or sprocket 328, attached to thesecond shaft 322, is connectable to the elongated roll bar member 18. Toprevent slippage and/or possible disengagement of the endless belt 330from the first and second wheels 326, 328 due to slack, the unit 300 maybe provided with an adjustable idler wheel 340 secured on shaft 342.Preferably, the circumference of the first wheel or sprocket 326 issmaller than the circumference of the wheel or second sprocket 328 sothat the motor 31 will be able to exert a greater amount of torque tothe roll bar member 18 than it would in the absence of the device. Itwill be appreciated that differences between the rotational speeds ofthe first and second sprockets 326, 328 will generally depend upon thenumber of teeth 327, 329 of each sprocket. For example, if the number ofteeth 327 on the first sprocket 326 is one half the number of teeth 329on the second sprocket 328, the first sprocket will rotate twice as fastas the second sprocket. However, the second sprocket 328 will have twicethe torque of the first sprocket 326. Or, if the number of teeth on thefirst sprocket is one third of the number of teeth on the secondsprocket, the first sprocket will rotate three times as fast as thesecond sprocket, while the second sprocket will have three times thetorque of the first sprocket. In a preferred embodiment, the ratio ofthe number of teeth of the first sprocket to the number of teeth of thesecond sprocket is in the range of about 1:1 to about 1:4. Morepreferably, the ratio is about 1:2. Even more preferably the firstsprocket has 12 teeth and the second sprocket has 26 teeth, for a ratioof about 1:2. In preferred embodiments, the motor itself will provide adrive ratio of from 60:1 to 120:1, preferably 90:1, which can then bemultiplied by the multiplier effect of the converter unit 300; which, ifit is 2:1, would result in a drive ratio of 180:1. Preferably, themultiplier effect of the converter unit 300, shown in FIGS. 19 and 20,is 2.16:1. The preferred motor and converter unit combination ratio is194.4:1. As noted in the earlier discussion of the worm gear typemotors, which are preferred as a part of the motive source 30 of thepresent invention, the design of the worm gear acts as a stop to preventunrolling of the roll bar member 18 when it is in a fully secured orclosed position.

Now also referring to FIG. 23, certain preferred embodiments, asadditionally discussed above, include a roll-up tarp apparatus having acrank arm assembly 400 for actuating movement of the elongated roll barmember 18. For example, the roll-up tarp apparatus 10 of FIG. 1 can beconfigured such that instead of including an arm 22 a having a motivesource 30, the apparatus includes a crank arm assembly 400 secured tothe inner tube 419 a of the elongated roll bar member. The crank armassembly 400 further includes a shaft 432. Preferably, the inner tube419 a and the shaft 432 include corresponding adaptors 442, 444 that canbe connected to form a universal joint 440. An operator can grasp androtate the shaft 432 such that the elongated roll bar member willcorrespondingly rotate to move the roll bar member into the secured oropen position, respectively.

Although the preferred embodiments of the present invention have beendescribed herein, the above description is merely illustrative. Furthermodification of the invention herein disclosed will occur to thoseskilled in the respective arts and all such modifications are deemed tobe within the scope of the invention as defined by the appended claims.

What is claimed is:
 1. A motorized roll-up tarp apparatus for attachmentto an open top truck trailer, the open top truck trailer having an opentruck box, the open truck box having a top opening, two ends and firstand second longitudinal sides, the motorized roll-up tarp apparatuscomprising: a flexible tarp, the flexible tarp having first and secondlateral edges and first and second longitudinal edges; wherein the firstlongitudinal edge can be interconnected to the first longitudinal sideof the truck box; an elongated roll bar member attached to the secondlongitudinal edge of the flexible tarp; the elongated roll bar memberhaving first and second ends; a latch plate that can extend along atleast a portion of the second longitudinal side of the truck box wheninterconnected thereto; a motive source interconnected to a converterunit; wherein the motive source includes a motor including a worm gearand the converter unit includes an input section and an output section;wherein the motive source is operatively connected to the input section,the input section is operatively connected to the output section and theoutput section is operatively connected to the elongated roll bar membersuch that force provided by the motive source is multiplied by theconverter unit and used to rotate the elongated roll bar member so as toselectively move the elongated roll bar member over the top opening ofthe truck box in both an unroll direction so as to position the flexibletarp in a secured position and a roll-up direction to position theflexible tarp in an open position when the first longitudinal edge isconnected to the first longitudinal side; an arm, the arm having an endinterconnected to the motive source and the converter unit and an endrotatably connected to the truck box; and a biasing member that canapply a tensioning force to the elongated roll bar member.
 2. Themotorized roll-up tarp apparatus of claim 1, wherein the elongated rollbar member is stored underneath the latch plate when the elongated rollbar member is in the secured position.
 3. The motorized roll-up tarpapparatus of claim 1, wherein the input section and the output sectionof the converter unit comprise first and second rotatable shafts, withthe first and second rotatable shafts driveably connected to each otherby an endless belt.
 4. The motorized roll-up tarp of claim 3, furthercomprising first and second wheels connected to the first and secondrotatable shafts, wherein the first and second wheels are drivinglyengaged by the endless belt.
 5. The motorized roll-up tarp apparatus ofclaim 1, wherein the input section and the output section of theconverter unit comprise first and second rotatable shafts, with thefirst and second rotatable shafts driveably connected to each other by achain.
 6. The motorized roll-up tarp of claim 5, further comprisingfirst and second sprockets connected to the first and second rotatableshafts, wherein the first and second sprockets are drivingly engaged bythe chain.
 7. The motorized roll-up tarp apparatus of claim 2, whereinthe motor has a drive ratio of from 60 to 1 to 120 to 1, which ismultiplied by the multiplier effect of the converter unit to which themotor is operatively interconnected.
 8. The motorized roll-up tarpapparatus of claim 2, wherein the elongated roll bar has a diameter ofabout 3 inches or more.
 9. A motorized roll-up tarp apparatus forattachment to an open top truck trailer, the open top truck trailerhaving an open truck box, the open truck box having a top opening, twoends and first and second longitudinal sides, the motorized roll-up tarpapparatus comprising: a flexible tarp, the flexible tarp having firstand second lateral edges and first and second longitudinal edges;wherein the first longitudinal edge can be interconnected to the firstlongitudinal side of the truck box; an elongated roll bar memberattached to the second longitudinal edge of the flexible tarp; theelongated roll bar member having first and second ends; a motive sourceinterconnected to a converter unit; wherein the motive source includes amotor including a worm gear and the converter unit includes an inputsection and an output section; wherein the motive source is operativelyconnected to the input section, the input section is operativelyconnected to the output section and the output section is operativelyconnected to the elongated roll bar member such that force provided bythe motive source is multiplied by the converter unit and used to rotatethe elongated roll bar member so as to selectively move the elongatedroll bar member over the top opening of the truck box in both an unrolldirection so as to position the flexible tarp in a secured position anda roll-up direction to position the flexible tarp in an open positionwhen the first longitudinal edge is connected to the first longitudinalside; an arm, the arm having an end interconnected to the motive sourceand the converter unit and an end rotatably connected to the truck box;a biasing member that can apply a tensioning force to the elongated rollbar member; and a latch plate secured to and extending along at least aportion of the second longitudinal side of the truck box; wherein theelongated roll bar member is stored underneath the latch plate when theelongated roll bar member is in the secured position.
 10. The motorizedroll-up tarp apparatus of claim 9, wherein the elongated roll bar has adiameter of about 3 inches or more.
 11. The motorized roll-up tarpapparatus of claim 9, wherein the motor has a drive ratio of from 60:1to 120:1, which is multiplied by the multiplier effect of the converterunit to which the motor is operatively interconnected.